That's silly. Microsoft sees the ARM-based tablet future, and doesn't want to miss out. But, they don't want to piss Intel off too bad, since they work hand in hand to develop Windows' interaction with Intel chips in desktop/server environments.
Saying ARM will only run Office and Metro apps is like saying Macbooks have the huge advantage of being able to run all Mac software to date. iOS will only run iOS apps. That's the point.
Also, the Intel tablet/laptop has the huge advantage of being able to run all Windows software to date. The ARM will only run Office and Metro apps.